I have joined as i am in need of some assistance with a project I am working on.

As a member of an active Vauxhall forum, I have been posting around trying to get some help with a project.

On most cars there is found an EGR valve ( exhaust gas recirculation) by where a metered amount of exhaust gas is put back into the combustion process to reduce emissions and also engine heat...the process that the valve creates also has the effect of making the car less responsive as the C02 is more...therefore less clean burning.

Now these devices were only fit by manufacturers to appease the "powers that be", when in actual fact the EGR process doesn't actually do a great deal to reduce emissions, a clean catalytic converter, good fuel and of course sensible driving is far more effective...A afiled or failing EGR makes the car sloppy, reduces smooth running and performance...also expensive to replace!

I have removed my EGR, blanked off the portal for it and installed a circuit to "cheat" the cars computer into thinking that the valve is there...

The circuit is 99% effective however it fails at a certain engine load range...some other hints I have is that the Relay used in the circuit, that accepts a command to operate, fails....or goes into a type of "pulse" by where it works too quickly or cannot handle the command...I have used a standard 12v DC relay as well as an automotive spec 12v DC relay that can handle upto 40 amps...

below is the pictures and schematics....as well as the wiring diagram of the EGR as it is on the car ( Haynes manual)

Both designs perform pretty much the same, although the first design is quicker to fail by a second or so..

What can I do to ensure the circuit can handle the switching process and volt load? I have read that swapping to a Transistor would help..but don't know where to start??